ATLANTA, Georgia (CNN) -- Willie "Pete" Williams had no idea when he was pulled over by police that the criminal justice system was about to steal away half his life.

Willie "Pete" Williams, 45, spent half of his life behind bars for a 1985 rape he did not commit.

Sitting in the flashing glow of Atlanta squad car lights along Georgia State Road 400, the 23-year-old part-time house painter didn't know police were looking for a rapist who had struck nearby three weeks earlier.

Police questioned -- and then arrested Williams, triggering a series of mistaken witness identifications that led to his unjust conviction for rape, kidnapping and aggravated sodomy.

It was 1985 and Williams was sentenced to serve 45 years in prison for a crime he didn't commit. "I felt betrayed. ... I felt like these people had taken my life for something I didn't do. I felt like I was being treated unfairly. ... I felt very, very angry towards everybody," said Williams last week, a free man after nearly 22 years behind bars.

Williams' troubling story provokes discomfort in a nation that prides itself on a justice system where the accused are innocent until proven guilty. So far, DNA evidence has directly exonerated 208 wrongly convicted people in the United States, according to the Innocence Project.It's unknown how many prisoners now locked up in American jails could be freed by new testing of DNA evidence.

A jury of Williams' peers convicted him in the April 5, 1985, rape, kidnapping and aggravated sodomy of a woman in Atlanta's Sandy Springs neighborhood.

The victim told police her attacker first approached her to ask if she could help him find someone named Paul. Then he produced a gun and forced her into her car, according to police. They then drove to a dead-end street where the assault occurred.

Because the science behind each person's unique DNA signature was new to police in 1985, the key evidence that sealed Williams' fate was the testimony of three eyewitnesses who mistakenly said they recognized him.

"Mistaken eyewitness identification has long been the single biggest factor in the conviction of innocents," said Barry Scheck, co-founder of the Innocence Project.

"That has got to be important to everybody, because if we can reform identification procedures, it will keep more innocent people out of jail and convict criminals who really commit the crimes."

A national nonprofit group, the Innocence Project has inspired creation of state and regional organizations including the Georgia Innocence Project, which exonerated Williams.

As a new prisoner Williams said he fought a painful struggle against the raw deal the world had dealt him. When board members denied him parole the first of three times Williams said, "they had to escort me to 'the hole' [solitary confinement]."

"I couldn't function out there around the other inmates," Williams said. "I was mad, I was bitter. I felt the whole world just gave me up."

It wasn't until 1997 -- more than a decade after he was locked away -- that Williams' own voice freed him from the grip of his anger. At Valdosta State Prison, a close friend named Charlie Brown helped him join a Christian choir -- leading him to accept Jesus.

"Singing was like being out here, in a sense. It freed me from all the things, from all the fights, from the officers who were cruel, prison, stabbings," said Williams, who especially embraced the hymn "Amazing Grace."

After singing got a hold of Williams, he said the hardest part of his heart started to dissolve.

"I didn't feel angry anymore -- or any hate."

Witness ID

Sequential double-blind lineups are standard in:

New Jersey

Suffolk County, Massachusetts

Northhampton, Massachusetts

Madison, Wisconsin

Hennepin County, Minnesota

Ramsey County, Minnesota

Winston-Salem, North Carolina

Santa Clara County, California

Virginia Beach, Virginia

Source: Innocence Project

To prevent more tragedies like Williams', innocence projects in many states, including Georgia, have begun pressing lawmakers to adopt special witness ID procedures called sequential double-blind lineups. Such lineups are administrated by officials who don't know who the suspect is and present each member of a lineup one-by-one instead of simultaneously.

Witnesses who see several potential suspects simultaneously are more likely to choose a person who looks most like the perpetrator -- but who may not actually be the perpetrator, according to the Innocence Project. The group also cites research that says misidentification is reduced if the person overseeing the lineup is "blind" to which person in the lineup is the suspect.

Georgia's Legislature held hearings Monday in Atlanta to study the research and the proposed standards, which have been adopted by New Jersey and jurisdictions in Minnesota, California and elsewhere.

Louis M. Dekmar, vice chair of the Commission on Accreditation for Law Enforcement Agencies is skeptical of the research, but said the issue deserves further study.

"I don't believe the research is so compelling that we need to make swings and changes that don't bode well for criminal investigations and the criminal justice process," said Dekmar, a 30-year law enforcement veteran and chief of police for LaGrange, Georgia.

Dekmar argues investigators should be allowed to administer lineups to gauge reaction while they look at witness faces, to see if a witness is "stressed, weeping, nervous -- all those reactions that help detectives formulate whether this is a strong identification or a weak identification."

Williams' Case

April 5, 1985: Woman raped, kidnapped in Atlanta, Georgia

Williams arrested: April 28, 1985

Sentence: 45 years in prison

Freed: January 23, 2007

Exonerated by DNA evidence: February 13, 2007

February 10, 2007: DNA tests result in arrest and eventual conviction of Kenneth G. Wicker for the 1985 rape

Sources: Innocence Project, Atlanta Journal-Constitution

Williams was convicted on the identification of three witnesses who first singled him out from a photo lineup, according to the Georgia Innocence Project.

More than 20 years later, Georgia Innocence Project attorneys arranged to compare Williams' DNA with DNA evidence collected from the 1985 rape. It was not a match, proving that Williams was not the attacker and opening the door to his release.

Shortly after Williams' exoneration, DNA science again played a role in the case when a genetic match resulted in the conviction and imprisonment of Kenneth G. Wicker for the crime that Williams had been wrongly convicted of. Years earlier Wicker had served four years in prison for another rape and two attempted sexual assaults, according to the Atlanta Journal Constitution.

As Scheck's Innocence Project marks its 15th year, the 1995 O.J. Simpson defense attorney describes it as a movement for criminal justice as well as human rights.

"I think that it's going to be remembered for getting innocents out of jail, but also for changing the paradigm in the criminal justice system," said Scheck.

"There is a greater understanding now that sound scientific and critical research can go a long way toward proving injustice and prosecuting the guilty."

Sometimes an Innocence Project client is confirmed to be guilty by DNA evidence, but the group doesn't make the number of those cases available. Theoretically, If key DNA material in a case is properly preserved, there's no time limit on revisiting old cases, according to the Innocence Project.

Critics accuse the group of denying closure to communities and victims' families by giving new life to old cases. To that, project spokesman Eric Ferrero said, "Victims are not served by the wrong people being convicted."

Perhaps the most important victory for the project has been its role in sparing the lives of 15 people condemned to death. In 2000, 13 condemned prisoners were exonerated by a group of Northwestern University students affiliated with the Innocence Project.

Some of the innocent prisoners were freed through DNA testing, others were exonerated after new trials were ordered by appellate courts.

Those spared lives prompted then-Illinois Gov. George Ryan to declare a state moratorium on all executions and later, a blanket clemency of all 167 death row prisoners.

The moratorium remains in effect while Illinois authorities consider proposed reforms to the system.

Back in Georgia, during the ten months since Williams' friends and family welcomed him home with hugs and kisses, he's been taking his time rejoining society, attending electronics classes and dealing with his top complaint: 21st century traffic.

Williams has found a home in a church congregation and plans to join its choir, holding on to the spiritual anchor he formed in prison.

Money is tight for Williams, and, according to the Innocence Project, only 45 percent of those exonerated by DNA evidence have been financially compensated. He expects some compensation from Georgia, although the state has no law guiding such cases.

Regaining his freedom has renewed Williams' belief in the power of prayer, but he said it has done little to repair his faith in the nation's justice system. He wonders how many other Americans are still suffering injustices like his own.

"When I see someone on television when they say, 'this is a suspect,' I have a difficult time believing that that actually is a suspect," Williams said.